Hydraulic control valves are commonly used in control of liquid flow, especially in watering systems such as sprinkler and dripper systems for watering lawns, for irrigation and the like. Such valves are commonly controlled by a solenoid; the movable plunger of the solenoid (the actuator), in the closed position, stops the flow of liquid by blocking the liquid flow, usually by closing a nozzle gate lock in the control flow path, and, in the open position, the solenoid allows liquid flow by removing the plunger from its blocking position.
Manual shutoff is a desirable feature for such valves. An example of the desirability of a manual shutoff is the situation where a valve has a leak or a problem has occurred in the water system but repair or replacement of the valve or repair of the problem in the water system must be delayed until a part or parts is available or the maintenance is completed. In order to avoid waste of water, it is desirable to shut the valve or valves off completely; no water should flow through the valve even if the automatic control is in the unblocking condition.
However, existing hydraulic control valves often only provide “fully automatic” or “manual off/on” operation; the valve can be turned on and off automatically and it can be turned off or on manually if the plunger is in blocking position, but when the plunger is in the unblocking position, putting the manual control in the shutoff position returns the device to automatic operation; there is no “manual off” setting in which automatic control is ignored so that no water flows even if the automatic control is in the unblocking position.
U.S. Pat. No. 3,500,844 discloses a lawn sprinkling system or the like including at least one solenoid actuated flow valve for controlling the flow of water to a sprinkling device, timer mechanism for regulating the operation of said valve and the flow of water there through, and an override arrangement for effecting the closing of said valve during periods of actual rainfall and for automatically restoring the operation of the valve to the control of the timer mechanism when the rainfall ceases. However, this system lacks a “manual on” feature, as described above.
U.S. Pat. No. 3,865,138 discloses a device having an inlet and an outlet and adapted to be connected directly to an outdoor water faucet by the inlet and be self-supporting thereby, and including an electrically controlled solenoid valve interposed between the inlet and outlet to control water flow there through, the solenoid valve being connected to an electrically operated timer and to a source of electrical power for the timed operation of the solenoid valve, and with there being a pair of key operated switches associated with the timer and solenoid valve for selecting either manual or automatic operation of the solenoid valve along with selectively de-energizing the solenoid valve during a timed operation cycle without having to wait for the timed cycle to end. However this system lacks a “manual on” feature, as described above.
It is therefore a long felt need to provide an automatic valve for controlling water flow that includes fully manual control.